This non-provisional application claims priority under 35 U.S.C. xc2xa7 119(a) on Patent Application No. 2001-213496 filed in Japan on Jul. 13, 2001, the entirety of which is hereby incorporated by reference.
1. Field of the Invention
This invention relates to a small sliding boat or personal watercraft (PWC) as they are more generally known, having an internal combustion engine with a supercharger incorporated therein. More particularly, the present invention relates to the arrangement of an intercooler and a cooling water passage of a personal watercraft of the type mentioned.
2. Description of Background Art
The power source in widespread personal watercrafts is conventionally a 2-cycle engine. However, it has been examined to use a 4-cycle engine for the power source in order to cope with reduction of pollution in recent years.
However, the output power of a 4-cycle engine is lower than that of a 2-cycle engine of the same total stroke volume. Accordingly, an engine with a supercharger and an intercooler have been examined in order to make up the power difference. The assignee of the present application has proposed a personal watercraft in Japanese Patent Laid-Open No. 2001-146197. In the above document, an internal combustion engine (engine) with a supercharger and an intercooler incorporated therein has been disclosed.
In this personal watercraft, a 4-cycle engine 2 with a supercharger 3 is incorporated in the inside of a body 1 as shown in FIGS. 9 and 10 of the present invention. A surge tank 4 and an intercooler 5, which communicate with an exhaust port of the engine, are provided between the supercharger 3 and the engine 2.
If it is attempted to dispose the surge tank 4 and the intercooler 5 between the supercharger 3 and the engine 2 in such a personal watercraft as described above, it is difficult to ensure the space for incorporation of the surge tank 4 and the intercooler 5 in a small space of the body 1. In particular, the space for incorporation of the intercooler 5 and the space for the layout of pipes for the intercooler 5 and surge tank 4 is insufficient. In the conventional personal watercraft shown in FIGS. 9 and 10, the intercooler 5 is disposed rearwardly downwardly of the surge tank 4.
Therefore, in the conventional personal watercraft, a comparatively great space S appears below the surge tank 4. Accordingly, there is a problem in that the small and precious space of the body is liable to suffer from insufficient use. Simultaneously, the space S is used to lay out the pipe 6 from the intercooler 5 to the surge tank 4. Accordingly, the lengthening of the pipe cannot be avoided. Furthermore, intake air cooled in the intercooler 5 is liable to be heated to a higher temperature in the process while it passes the pipe 6. Therefore, there is a problem also in that the cooling effect of the intake air is reduced by a temperature rise to decrease the intensity of the intake air, resulting in a drop of output power of the engine.
Furthermore, with the personal watercraft according to the background art, a water supply structure for the intercooler 5 is uncertain.
An object of the present invention resides in solutions to the problems described above to provide a personal watercraft having an internal combustion engine with a supercharger incorporated therein, wherein the small and precious space in the body can be utilized efficiently, and simultaneously the output power can be augmented.
Another object of the present invention resides in the provision of a personal watercraft having an internal combustion engine with a supercharger incorporated therein which has a suitable water supply structure for an intercooler.
In order to attain the object described above, according to a first aspect of the present invention, a personal watercraft having an internal combustion engine with a supercharger incorporated therein is incorporated in the inside of a body composed of a hull and a deck. A surge tank and an intercooler, which communicate with an intake port of the internal combustion engine, are provided between the supercharger and the internal combustion engine. Furthermore, the intercooler is disposed just below the surge tank.
According to a second aspect of the present invention, the personal watercraft having an internal combustion engine with a supercharger incorporated therein according to the first aspect of the present invention includes the intercooler having an intake entrance from the supercharger and an exit to the surge tank at an upper portion thereof. The intake entrance is provided adjacent the supercharger disposed on one side of the internal combustion engine, while the exit is provided adjacent the other end of the internal combustion engine.
According to a third aspect of the present invention, a personal watercraft having an internal combustion engine with a supercharger incorporated therein includes a water cooled intercooler disposed in an intake system of the internal combustion engine. The personal watercraft has a cooling water passage for taking in cooling water to be supplied to the intercooler from the outside of the personal watercraft and supplying the cooling water to the intercooler.
According to a fourth aspect of the present invention, the personal watercraft having an internal combustion engine with a supercharger incorporated therein according to the third aspect of the present invention includes the cooling water passage, which communicates a jet pump for propelling the personal watercraft and the intercooler with each other.
According to a fifth aspect of the present invention, the personal watercraft having an internal combustion engine with a supercharger incorporated therein according to either of the third or fourth aspects of the present invention includes the cooling water passage, which communicates a jet pump for propelling the personal watercraft and the intercooler directly with each other.
According to a sixth aspect of the present invention, the personal watercraft having an internal combustion engine with a supercharger incorporated therein according to the third through fifth aspects of the present invention includes the intercooler, which has an intake entrance from the supercharger and an exit to the surge tank. The cooling water is supplied from the intake entrance side into the intercooler.
With the personal watercraft having an internal combustion engine with a supercharger incorporated therein according to the first aspect of the present invention, the internal combustion engine with the supercharger is incorporated in the inside of the body formed from the hull and the deck. Furthermore, the surge tank and the intercooler, which are in communication with the intake port of the internal combustion engine, are provided between the supercharger and the internal combustion engine. In addition, the intercooler is disposed just below the surge tank. Accordingly, the space below the surge tank can be utilized efficiently. As a result, the small and precious space in the body can be utilized efficiently.
Simultaneously, the intercooler is disposed just below the surge tank. Accordingly, the pipe from the intercooler to the surge tank can be formed to a minimum length. Accordingly, the temperature rise of intake air while the intake air passes the pipe can be reduced. As a result, the cooling effect of intake air (intake air density) can be augmented to augment the output power of the internal combustion engine.
With the personal watercraft having an internal combustion engine with a supercharger incorporated therein according to the second aspect of the present invention, the intercooler has, at an upper portion thereof, the intake entrance from the supercharger and the exit to the surge tank. The intake entrance is provided adjacent the supercharger disposed on one side of the internal combustion engine, while the exit is provided adjacent the other side of the internal combustion engine. Accordingly, in addition to the above advantages of the first aspect of the present invention, the supercharger, intercooler and surge tank can be connected to each other by short pipes.
In addition, the intake entrance of the intercooler and the supercharger can be connected to each other making use of the connection space (space formed between the surge tank and the intercooler below the surge tank) between the exit of the intercooler and the surge tank positioned just above the intercooler. Accordingly, the small and precious space in the body can be utilized further efficiently.
With the personal watercraft having an internal combustion engine with a supercharger incorporated therein according to the third aspect of the present invention, the personal watercraft includes the water-cooled intercooler disposed in the intake system of the internal combustion engine and the cooling water passage for taking in cooling water to be supplied to the intercooler from the outside of the personal watercraft and supplying the cooling water to the intercooler. Therefore, the intercooler is cooled with water of a low temperature taken in from the outside of the personal watercraft. Accordingly, the necessity for any other heat exchanger for cooling the intercooler is eliminated.
With the personal watercraft having an internal combustion engine with a supercharger incorporated therein according to the fourth aspect of the present invention, the cooling water passage communicates the jet pump for propelling the personal watercraft and the intercooler with each other. Therefore, the supply of cooling water to the intercooler is performed from the jet pump through the cooling water passage. Accordingly, in addition to the above advantages of the third aspect of the present invention, the necessity for any other pump for supplying cooling water to the intercooler is eliminated.
With the personal watercraft having an internal combustion engine with a supercharger incorporated therein according to the fifth aspect of the present invention, the cooling water passage communicates the jet pump for propelling the personal watercraft and the intercooler directly with each other. Therefore, the intercooler is cooled directly without any other cooled member (for example, the internal combustion engine) with cooling water from the jet pump. Accordingly, in addition to the above advantages of the third and fourth aspects of the present invention, the density of intake air and the output power of the internal combustion engine are further augmented.
With the personal watercraft having an internal combustion engine with a supercharger incorporated therein according to the sixth aspect of the present invention, the intercooler has the intake entrance from the supercharger and the exit to the surge tank and the cooling water is supplied from the intake entrance side into the intercooler. Therefore, the intake entrance side at which the temperature is higher in the intercooler is cooled efficiently. Accordingly, in addition to the above advantages of the third through fifth aspects of the present invention, the cooling effect of intake air by the entire intercooler and the output power of the internal combustion engine are further augmented.
Further scope of applicability of the present invention will become apparent from the detailed description given hereinafter. However, it should be understood that the detailed description and specific examples, while indicating preferred embodiments of the invention, are given by way of illustration only, since various changes and modifications within the spirit and scope of the invention will become apparent to those skilled in the art from this detailed description.